/*They test whether everything is right with the world as far as your program is concerned.
Usually, they live in your code to make sure you don’t have any inconsistencies
in your logic, performing tasks such as checking invariants at the
beginning and end of a method or ensuring that method parameters are valid*/

assert ( true )
assert 1 == 1
def x = 1
assert x == 1
def y = 1 ; assert y == 1

assert '12345' =~ /\d+/

assert 'xxxxx' == '12345'.replaceAll(/\d/,'x')

def t = 1
def g = 2
assert t + g == 3
assert t.plus(g) == 3
assert t instanceof Integer     
